Started to get the dreaded 'sensor rot' . Black spots on images not caused by crud on the sensor , but 'corrosion' on the sensor cover glass coating . It's a known issue with M9's to the point that Leica had a replacement program (which , of course, ended last year) . The replacement sensors are allegedly redesigned to be resistant to the problem .Thought I'd dodged the bullet on this , but guess not . So it's in the hands of the white coated technicians at Leica Allendale , and , upon its return , it'll have sense , but I won't have dollars .